/**
* Same as before, but perform alpha-beta pruning.
* The main routine should make the call with
* alpha = COMP_LOSS and beta = COMP_WIN.
*/
int TicTacToe::findCompMove( int & bestMove, int alpha, int beta )
{
int i, responseValue;
int dc; // dc means don't care; its value is unused
int value;
if( fullBoard( ) )
value = DRAW;
else
if( immediateCompWin( bestMove ) )
return COMP_WIN; // bestMove will be set by immediateCompWin
else
{
value = alpha; bestMove = 1;
for( i = 1; i <= 9 && value < beta; i++ ) // Try each square
{
if( isEmpty( i ) )
{
place( i, COMP );
responseValue = findHumanMove( dc, value, beta );
unplace( i ); // Restore board
if( responseValue > value )
{
// Update best move
value = responseValue;
bestMove = i;
}
}
}
}
return value;
}
void fullBoard_notices_an_empty_board(CuTest *tc) {
int board[3][3];
ct_initialize(3, 3, board);
board[0][1] = 0;
board[0][2] = 0;
board[1][0] = 0;
board[1][1] = 0;
board[1][2] = 0;
board[2][0] = 0;
board[2][1] = 0;
board[2][2] = 0;
int answer = fullBoard(3, 3, board);
CuAssertIntEquals_Msg(tc, "Full board", -1, answer);
}